could you help me on the investment post

I think Ms Sue's answer is as good as we can give.

This does not look like a math question, because there are no specifics.

By specifics, I mean if Erik had a choice of different investments with different returns over different periods, then perhaps there would be a choice to be made among the different options.

The question as it is requires a research into what's available in the market, calculate and determine the best choice of the options.

As Ms Sue mentioned, the tax implications have to be factored in.

All these are country/state/market dependent, and there is not a single mathematical answer, sorry.